1. Field of the Invention
The present invention relates to a flashless rocket propellant. More particularly, the flashless rocket propellant of the present invention contains a continuous potassium sulfate rod that effectively removes the flash signature of the rocket. The flashless rocket propellant is useful in such rocket motors as the MK 66 Rocket Motor.
2. Brief Description of the Related Art
The United States Navy uses the MK 66 Rocket Motor which contains a small potassium sulfate (spelled also as potassium sulphate) rod to partially suppress motor plume flash. Generally, MK 66 Rocket Motors contain a small potassium sulfate (K.sub.2 SO.sub.4) salt rod bonded to a stabilizing rod to suppress the motor plume flash and help control combustion instability. The potassium sulfate rod has a constant diameter with a 0.33 inch diameter. The K.sub.2 SO.sub.4 suppresses the plume flash by preventing the fuel rich exhaust products, primarily CO and H.sub.2, from reacting with atmospheric oxygen.
The MK 66 Rocket Motor is a 2.75 inch rocket system designed to be operated from rotary and fixed wing aircraft. The rocket motor delivers a variety of warheads which include high explosive and submunition warheads. The 2.75 inch MK 66 Rocket Motor produces a bright exhaust flash which is visible to approximately 800 feet.
The addition of significant amounts of K.sub.2 SO.sub.4 to the double-base propellant mix, for rocket motor plume flash suppression, has been found to adversely affect the ballistic performance of the rocket motor. Increased amounts of potassium sulfate within the rocket motor create over-pressurization within motor tube, causing failure. Accordingly, the volume of K.sub.2 SO.sub.4 in the MK 66 has been limited for performance criteria. This limited amount of potassium sulfate for release into the exhaust stream is generally insufficient for rendering the complete burning time of the rocket motor flashless.
Several patents disclose the use of potassium sulfate compositions: U.S. Pat. No. 3,166,896 to Breitengross, Jr. et al.; U.S. Pat. No. 3,951,706 to Eldridge; U.S. Pat. No. 3,960,621 to Whitworth, et al.; U.S. Pat. No. 3,985,594 to Bjorn; U.S. Pat. No. 4,381,270 to Bjorn, et al.; U.S. Pat. No. 4,642,983 to Melvin et al.; U.S. Pat. No. 4,701,228 to Lagreze; and U.S. Pat. No. 5,565,643 to Raines, et al. In these references, potassium sulphate is disclosed within flash suppressive propellant compositions. However, none of the patents discloses a structure or mechanism for adding significant amounts of the potassium sulfate with a burning propellant to create a flashless rocket plume without adversely affecting the critical performance of the rocket.
In view of the foregoing, there is a need for flashless rocket motor that does not impede the proper burning of the rocket propellant. The present invention addresses this and other needs.